The inventive concepts relate to methods of manufacturing semiconductor devices including a transistors, and more particularly, to semiconductor devices including transistors using a high-dielectric constant (k) gate insulation layer.
In order to increase the integration density of semiconductor devices, it may be desirable to form the gate insulation layers of transistors in the device using a material with a high dielectric constant (i.e., a high-k material). However, when a high-k gate insulation layer is used, the threshold voltage of the semiconductor device may be changed and the flat band voltage of the device may be increased, which can adversely affect the electrical characteristics of the semiconductor device.